At a glance
- A water exploitation index of 20 % or above indicates the threshold of water stress.
- Water stress means an increasing risk of environmental problems and economic difficulties.
- Since 2004 the water exploitation index has been below the critical level of 20 %. Without cooling water the value is far below 20 %.
- Germany is causing water exploitation in other parts of the world by importing goods. In some regions this can contribute to water stress.
The water exploitation index shows the level of water abstraction in Germany, measured against the renewable water resources. A use of the water resources above 20% is considered as water stress in international terms. Using too much water can lead to environmental problems and hinder economic development (Raskin et al. 1997). For instance, groundwater resources near the coast can become saline due to the penetration of seawater. Falling groundwater levels can lead to the drying out and loss of marshes and wetlands.
Although there is generally no water stress in Germany, there are regional and seasonal differences. Precipitation is very unevenly distributed in Germany. Regions such as Brandenburg and Saxony-Anhalt have particularly low precipitation. Other regions, e.g. the Alpine foothills, have particularly high levels of precipitation.
The indicator should have a regional reference added in future. This would enable the water exploitation index to be specifically identified on a regional basis and regions with potential water stress could be shown. Indicators of this kind are currently being developed.
Assessing the development
In its Roadmap to a Resource Efficient Europe the European Commission has set a target of not exceeding the 20 % threshold value for the water exploitation index (EC 2011). In Germany the index fell from 24.6 % to 12.8 % between 1991 and 2016. The reason for this development is a continuous decline in water abstraction in Germany. In 1991 it was still 46.3 billion cubic metres (m³) while in 2016 it was about 48 % less, at 24.1 billion m³.
Large amounts of the water volume are used for cooling and are returned after use. If this is included in the calculation, then the water exploitation index would be considerably below 10 %. The sharp fall in water abstraction between 2010 and 2013 was largely due to the lower use of cooling water in conventional power plants.
There is no water stress in Germany itself. However, the German economy contributes to water usage in other countries through the import of water-intensive goods. This can cause water stress in some places, depending on the local conditions.
The indicator compares water abstraction with potential water resources. Calculating the water resources includes inflow from other countries and the difference between precipitation and evaporation from soils and plants. The mean of the period from 1961 to 1990 is used for calculating the index. Water abstraction is recorded by the Federal Statistical Office of Germany and published every three years in the ‘Fachserie 19 Reihe 2.1.1 and 2.2’ (Destatis 2018, in German only). These technical series also include guidelines on collecting the data.
More detailed information: 'Wasserressourcen und ihre Nutzung' (in German only).